A review and comparative assessment of existing approaches to calculate material footprints
Effective implementation of resource policies requires consistent and robust indicators. An increasing number of national and international strategies focussing on resource efficiency as a means for reaching a “green economy” call for such indicators. As supply chains of goods and services are increasingly organised on the global level, comprehensive indicators taking into account upstream material flows associated with internationally traded products need to be compiled. Particularly in the last few years, the development of consumption-based indicators of material use – also termed “material footprints” – has made considerable progress. This paper presents a comprehensive review of existing methodologies to calculate material footprint-type indicators. The three prevailing approaches, i.e. environmentally extended input–output analysis (EE-IOA), coefficient approaches based on process analysis data, and hybrid approaches combing elements of EE-IOA and process analysis are presented, existing models using the different approaches discussed, and advantages and disadvantages of each approach identified. We argue that there is still a strong need for improvement of the specific approaches as well as comparability of results, in order to reduce uncertainties. The paper concludes with recommendations for further development covering methodological, data and institutional aspects.